Microscope objective

ABSTRACT

A eight component, oil-immersion, apochromatic microscope objective has a numerical aperture of 1.30. When used with a telescope as described in U.S. Pat. No. 3,355,234, the objective provides a magnification of 100 X in an embodiment having a focal length of 1.824 mm and is well corrected for the usual chromatic image aberrations, spherical aberration, coma and astigmatism.

BACKGROUND OF THE INVENTION

This invention relates to microscope objectives and more particularly to apochromatic microscope objectives having a numerical aperture of substantially 1.30 and a magnification of 100X, when used with a telescope objective as described in U.S. Pat. No. 3,355,234 and having a focal length of 1.824 mm.

Microscope objectives according to this invention are well corrected for the usual chromatic image aberrations, spherical aberration, coma and astigmatism when used with a telescope objective and have a substantially flat image field.

U.S. Pat. No. 3,700,311, issued Oct. 24, 1972, discloses an eight element, oil-immersion, apochromatic microscope objective having an N.A. of 1.30. The specific ranges of curves, thicknesses, spacings, indices of refraction and Abbe numbers, as well as the preferred embodiments are different, although the general configuration is the same as that of the present invention.

DESCRIPTION OF THE DRAWING AND INVENTION

The drawing is an optical diagram of an embodiment of the present invention.

Referring to the drawing, objective XX is shown in a view transverse to its optical axis relative to object plane 0 and illustrates the lens components aligned along the optical axis. The first component I of objective XX is a plano-convex positive doublet followed by a concavo-convex positive singlet II. A biconvex positive doublet III is next succeeded by a concavo-convex positive doublet IV and a convex-concavo positive doublet V. A biconvex positive doublet VI, convex-concavo negative singlet VII and concavo-convex positive singlet complete objective XX.

The parameters of objectives according to the present invention are set forth in Table I, wherein successive axial spaces are identified as S₁ to S₈ and axial thicknesses of successive lens elements are identified as T₁ to T₁₄. The radii of successive lens surfaces are designated R₁ to R₂₂ with the minus sign (-) being applied to the radius of a surface whose center of curvature lies on the object side of its vertex. The refractive indices and Abbe numbers of the successive lenses are absolute values designated ND₁ to ND₁₄ and ν₁ to ν₁₄ successively.

                                      TABLE I                                      __________________________________________________________________________                              Refractive Abbe                                          Radius  Thickness                                                                             Spacing                                                                               Index      No                                         Lens                                                                              (R)     (T)    (S)    (ND)       (ν)                                     __________________________________________________________________________                       S.sub.1 = 0.154F                                                R.sub.1 = ∞                                                                      T.sub.1 = 0.313F                                                                             1.535 < ND.sub.1 < 1.545                                                                  50.5 < ν.sub.1 < 51.5                   I  R.sub.2 = -0.583F                                                                      T.sub.2 = 1.568F                                                                             1.88 < ND.sub.2 < 1.89                                                                    41.5 < ν.sub.2 < 42.5                      R.sub.3 = -1.356F                                                                             S.sub.2 = 0.011F                                                R.sub.4 = -9.156F                                                           II         T.sub.3 = 1.118F                                                                             1.78 < ND.sub.3 < 1.79                                                                    50 < ν.sub.3 < 51                          R.sub.5 = -3.632F                                                                             S.sub.3 = 0.291F                                                R.sub.6 = 8.123F                                                                       T.sub.4 =  0.658F                                                                            1.715 < ND.sub.4 < 1.725                                                                  34 < ν.sub.4 < 35                       III                                                                               R.sub.7 = 4.399F                                                                       T.sub.5 = 2.577F                                                                             1.43 < ND.sub.5 < 1.44                                                                    95 < ν.sub.5 < 96                          R.sub.8 = 4.399F                                                                              S.sub.4 = 0.252F                                                R.sub.9 = -21.809F                                                                     T.sub.6 = 0.658F                                                                             1.65 < ND.sub.6 < 1.66                                                                    39 < ν.sub.6 < 40                       IV R.sub.10 = 3.907F                                                                      T.sub.7 = 2.248F                                                                             1.43 < ND.sub.7 < 1.44                                                                    95 < ν.sub.7 < 96                          R.sub.11 = 7.204F                                                                             S.sub.5 = 0.055F                                                R.sub.12 = 5.212F                                                                      T.sub.8 = 2.193F                                                                             1.43 < ND.sub.8 < 1.44                                                                    95 < ν.sub.8 < 96                       V  R.sub.13 =  -5.869F                                                                    T.sub.9 = 0.658F                                                                             1.715 < ND.sub.9 < 1.725                                                                  34 < ν.sub.9 < 35                          R.sub.14 = 10.204F                                                                            S.sub.6 = 0.055F                                                R.sub.15 = 6.014F                                                                      T.sub.10 = 1.919F                                                                            1.43 < ND.sub.10 < 1.44                                                                   95 < ν.sub.10 < 96                      VI R.sub.16 = -6.014F                                                                     T.sub.11 = 0.658F                                                                            1.715 < ND.sub.11 < 1.725                                                                 34 < ν.sub.11 < 35                         R.sub.17 = -6.014F                                                                            S.sub.7 = 0.055F                                                R.sub.18 = 6.272F                                                           VII        T.sub.12 = 2.193F                                                                            1.62 < ND.sub.12 < 1.63                                                                   46.5 < ν.sub.12 < 47.5                     R.sub.19 = 3.098F                                                                             S.sub.8 = 1.069F                                                R.sub.20 = -2.209F                                                                     T.sub.13 =  0.987F                                                                           1.785 < ND.sub.13 < 1.795                                                                 47 < ν.sub.13 < 48                      VIII                                                                              R.sub.21 = 3.410F                                                                      T.sub.14 = 1.645F                                                                            1.78 < ND.sub.14 < 1.79                                                                   25.5 < ν.sub.14 < 26.5                     R.sub.22 = -5.943F                                                          __________________________________________________________________________

wherein F is 1.80 to 1.85 mm.

A preferred embodiment of the present invention wherein F is 1.824 has the following parameters.

                                      TABLE II                                     __________________________________________________________________________                             Refractive                                                                             Abbe                                              Radius  Thickness                                                                             Spacing                                                                              Index   No                                             Lens                                                                              (R)     (T)    (S)   (ND)    (ν)                                         __________________________________________________________________________                       S.sub.1 = 0.28                                                  R.sub.1 = ∞                                                                      T.sub.1 = 0.57                                                                              ND.sub.1 = 1.540                                                                       ν.sub.1 = 51.1                              I  R.sub.2 = -1.063                                                                       T.sub.2 = 2.68                                                                              ND.sub.2 = 1.883                                                                       ν.sub.2 = 40.8                                 R.sub.3 = -2.473                                                                              S.sub.2 = 0.02                                                  R.sub.4 = -16.700                                                           II         T.sub.3 = 2.04                                                                              ND.sub.3 = 1.786                                                                       ν.sub.3 = 50.2                                 R.sub.5 = -6.625                                                                              S.sub.3 = 0.53                                                  R.sub.6 = 14.816                                                                       T.sub.4 = 1.20                                                                              ND.sub.4 = 1.720                                                                       ν.sub.4 = 34.6                              III                                                                               R.sub.7 = 8.023                                                                        T.sub.5 = 4.70                                                                              ND.sub.5 = 1.434                                                                       ν.sub.5 = 95.6                                 R.sub.8 = -8.023                                                                              S.sub.4 = 0.46                                                  R.sub.9 = 39.779                                                                       T.sub.6 = 1.20                                                                              ND.sub.6 = 1.654                                                                       ν.sub.6 = 39.6                              IV R.sub.10 = 7.127                                                                       T.sub.7 = 4.10                                                                              ND.sub.7 = 1.434                                                                       ν.sub.7 = 95.6                                 R.sub.11 = -13.140                                                                            S.sub.5 = 0.10                                                  R.sub.12 = 9.507                                                                       T.sub.8 = 4.00                                                                              ND.sub.8 = 1.434                                                                       ν.sub.8 = 95.6                              V  R.sub.13 = -10.705                                                                     T.sub.9 = 1.20                                                                              ND.sub.9 = 1.720                                                                       ν.sub.9 = 34.6                                 R.sub.14 = 18.612                                                                             S.sub.6 = 0.10                                                  R.sub.15 =  10.970                                                                     T.sub.10 = 3.50                                                                             ND.sub.10 = 1.434                                                                      ν.sub.10 = 95.6                             VI R.sub.16 = -10.970                                                                     T.sub.11 = 1.20                                                                             ND.sub.11 = 1.720                                                                      ν.sub.11 = 34.6                                R.sub.17 = -10.970                                                                            S.sub.7 = 0.10                                                  R.sub.18 = 11.440                                                           VII        T.sub.12 = 4.00                                                                             ND.sub.12 = 1.624                                                                      ν.sub.12 = 47.0                                R.sub.19 = 5.650                                                                              S.sub.8 = 1.95                                                  R.sub.20 = -4.029                                                                      T.sub.13 = 1.80                                                                             ND.sub.13 = 1.788                                                                      ν.sub.13 = 47.4                             VIII                                                                              R.sub.21 = 6.220                                                                       T.sub.14 = 3.00                                                                             ND.sub.14 = 1.784                                                                      ν.sub.14 = 26.1                                R.sub.22 = -10.840                                                          __________________________________________________________________________ 

What is claimed is:
 1. An eight component, oil immersion apochromatic objective having an N.A. of 1.30 which has a plano-convex doublet I, a concavo-convex singlet II, a biconvex doublet III, a concavo-convex doublet IV, a convex-concavo doublet V, a biconvex doublet VI, a convex-concavo singlet VII and a concavo-convex doublet VIII having the parameters of the respective axial spacings (S₀ -S₈) in mm, radii (R₁ -R₂₂), in mm with a minus sign (-) indicating a center of curvature on the object side of the lens, thickness (T₁ -T₁₄) in mm, indices of refraction (ND₁ -ND₁₄) and Abbe numbers (ν₁ -ν₁₄) are absolute values, all being determined by the following table:

    ______________________________________                                         RefractiveAbbe                                                                 RadiusThicknessSpacingIndexNo                                                  Lens(R)(T)(S)(ND)(ν)                                                        ______________________________________                                         S.sub.1 =0.154F                                                                R.sub.1 =∞                                                               T.sub.1 =0.313F1.535<ND.sub.1 <1.54550.5<ν.sub.1 <51.5                      IR.sub.2 =-0.583F                                                              T.sub.2 =1.568F1.88<ND.sub.2 <1.8941.5<ν.sub.2 <42.5                        R.sub.3 =-1.356F                                                               S.sub.2 =0.011F                                                                R.sub.4 =-9.156F                                                               IIT.sub.3 =1.118F1.78<ND.sub.3 <1.7950<ν.sub.3 <51                          R.sub.5 =-3.632F                                                               S.sub.3 =0.291F                                                                R.sub.6 =8.123F                                                                T.sub.4 =0.658F1.715<ND.sub.4 <1.72534<ν.sub.4 <35                          IIIR.sub.7 =4.399F                                                             T.sub.5 =2.577F1.43<ND.sub.5 <1.4495<ν.sub.5 <96                            R.sub.8 =-4.399F                                                               S.sub.4 =0.252F                                                                R.sub.9 =-21.809F                                                              T.sub.6 =0.658F1.65<ND.sub.6 <1.6639<ν.sub.6 <40                            IVR.sub.10 =3.907F                                                             T.sub.7 = 2.248F1.43<ND.sub.7 <1.4495<ν.sub.7 <96                           R.sub.11 =7.204F                                                               S.sub.5 =0.055F                                                                R.sub.12 =5.212F                                                               T.sub.8 =2.193F1.43<ND.sub.8 <1.4495<ν.sub.8 <96                            VR.sub.13 =-5.869F                                                             T.sub.9 =0.658F1.715<ND.sub.9 <1.72534<ν.sub.9 <35                          R.sub.14 =10.204F                                                              S.sub.6 =0.055F                                                                R.sub.15 =6.014F                                                               T.sub.10 =1.919F1.43<ND.sub.10 <1.4495<ν.sub.10 <96                         VIR.sub.16 =-6.014F                                                            T.sub.11 =0.658F1.715<ND.sub.11 <1.72534<ν.sub.11 <35                       R.sub.17 =-6.014F                                                              S.sub.7 =0.055F                                                                R.sub.18 =6.272F                                                               VIIT.sub.12 =2.193F1.62<ND.sub.12 <1.6346.5<ν.sub.12 <47.5                  R.sub.19 =3.098F                                                               S.sub.8 =1.069F                                                                R.sub.20 =-2.209F                                                              T.sub.13 =0.987F1.785<ND.sub.13 <1.79547<ν.sub.13 <48                       VIIIR.sub.21 =3.410F                                                           T.sub.14 =1.645F1.78<ND.sub.14 <1.7925.5<ν.sub. 14 <26.5                    R.sub.22 =-5.943F                                                              ______________________________________                                    

wherein R is 1.80 to 1.85 mm.
 2. The microscope objective according to claim 1 wherein F is 1.824, ND₁ is 1.540, ND₂ is 1.883, ND₃ is 1.786, ND₄, ND₉ and ND₁₁ are 1.720, ND₅, ND₇, ND₈ and ND₁₀ are 1.434, ND₆ is 1.654, ND₁₂ is 1.624, ND₁₃ is 1.788, ND₁₄ is 1.784, ν₁ is 51.1, ν₂ is 40.8, ν₃ is 50.2, ν₄, ν₉ and ν₁₁ are 34.6, ν₅, ν₇, ν₈ and ν₁₀ are 95.6, ν₆ is 39.6, ν₁₂ is 47, ν₁₃ is 47.4 and ν₁₄ is 26.1. 